Dusty: A Teleoperated Assistive Mobile Manipulator that Retrieves Objects from the Floor

Abstract

Retrieval of dropped objects has consistently been ranked as a high priority task for assistive robots. We have previously presented a dustpan-inspired end effector capable of robustly grasping objects from the floor. In this paper, we present and evaluate Dusty, a complete mobile manipulator consisting of a new version of this end effector, a mobile base, a scissor lift, and a wireless interface. The interface consists of a joystick for driving, a button that triggers a grasping behavior, and a button that operates the lift. We first tested Dusty’s ability to grasp objects from 25 object categories prioritized for robotic retrieval by people with ALS. Dusty succeeded in 97.6% of the 125 trials and grasped each object no fewer than 3 out of 5 times. We then tested Dusty’s ability to grasp a small, thin cylinder (ca. 2.92cm diameter and 0.71cm height) placed at different locations. Grasping succeeded when the object was in a large region in front of the robot (ca. 15cm x 38cm), which we expect to improve usability. In preparation for testing with motor-impaired subjects, we conducted a pilot study with able-bodied subjects (n=10) in which each subject drove Dusty around an obstacle, picked up an object, and then delivered the object to him or herself, all while sitting in a stationary wheelchair. The subjects succeeded at this task in all 30 trials (3 trials each) with a mean completion time of 67.8 seconds (SD = 20.8 s). Our results suggest that assistive robots like Dusty could be useful for retrieving dropped objects and enhancing quality of life.